Although 80-90 percent of acute temporomandibular disorder (TMD) patients can be expected to improve with no long-term problems after standard, non- surgical treatment, the remaining 10-20 percent go on to experience chronic difficulties. Unfortunately, there has been very little systematic research attempting to isolate useful predictors of when acute TMD will likely develop into a more chronic and costly disability. The first major goal of the present proposed project is to evaluate whether use of the recently developed Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), along with DSM-III-R (American Psychiatric Association) Axis I and Axis II diagnoses derived from a structured interview format, will serve as useful predictors for those acute TMD patients who subsequently develop chronic TMD problems. In order to accomplish this goal, 1600 acute TMD patients (symptoms less than six months duration) will be prospectively followed over a one-year period in order to determine whether the presence of DSM-III-R disorders and certain RDC\TMD variables in the acute stage are predictive of the development of chronicity. Those acute TMD patients who subsequently develop chronic problems will participate in the second phase of this proposed project which will evaluate the relative efficacy of four techniques in treating these chronic TMD patients: (1) continuation of non-surgical treatment alone; (2) relaxation-biofeedback treatment; (3) behavioral-cognitive treatment; (4) combined relaxation-biofeedback and behavioral-cognitive treatment. These four groups will be balanced for type of patient: one subgroup of patients will have met diagnostic criteria for current major depression at the time of initial assessment during Phase 1; the other subgroup will have been diagnosed as not depressed and not having any major psychopathology. It is hypothesized that for those who have a major psychological overlay such as depression, a treatment program including procedures specifically directed at dealing with this disorder (i.e., behavioral-cognitive therapy) is necessary for therapeutic improvement of chronic TMD. For those who have significant psychological and physical concomitants, a combined treatment procedure will be most efficacious. Such results will further demonstrate that chronic TMD is a complex psychophysiological disorder involving both physical and psychological factors, with the relative contribution of these two factors depending upon premorbid characteristics of the particular individual.